Haloperoxidases form a class of enzymes which are able to oxidize halides (X=Cl-, Br-, or I-) in the presence of hydrogen peroxide to the corresponding hypohalous acid (HOX) according to: EQU H.sub.2 O.sub.2 +X-+H+.fwdarw.H.sub.2 O+HOX
If a convenient nucleophilic acceptor is present, a reaction will occur with HOX whereby a diversity of halogenated reaction products may be formed.
A chloride peroxidase (EC 1.11.1.10) is an enzyme capable of oxidizing chloride, bromide and iodide ions with the consumption of H.sub.2 O.sub.2.
A bromide peroxidase is an enzyme capable of oxidizing bromide and iodide ions with the consumption of H.sub.2 O.sub.2.
A iodide peroxidase (EC 1.11.1.8) is an enzyme capable of oxidizing iodide ions with the consumption of H.sub.2 O.sub.2.
Vanadium haloperoxidases are different from other haloperoxidases in that the prosthetic group in theses enzymes have structural features similar to vanadate (vanadium V), whereas the other haloperoxidases are hemeperoxidases.
Haloperoxidases have been isolated from various organisms: mammals, marine animals, plants, algae, a lichen, fungi and bacteria (for reference see Biochimica et Biophysica Acta 1161, 1993, pp. 249-256). It is generally accepted that haloperoxidases are the enzymes responsible for the formation of halogenated compounds in nature, although other enzymes may be involved.
The amino acid sequence (SEQ No. 1) for the vanadium-containing chloroperoxidase from the fungus Curvularia inaequalis has been published (see SWISS-PROT:P49053).
The amino acid sequence (SEQ No. 2) for the vanadium-containing chloroperoxidase from the fungus Curvularia verruculosa has been published (see WO 97/04102).
The X-ray structure of the vanadium-containing chloroperoxidase from the fungus Curvularia inaequalis has been published (Proc. Natl. Acad. Sci. U.S.A., 93(1), 1996, 392-396; and pdblvnc.ent).
Haloperoxidases are of current interest because of their broad range of potential industrial uses. For example, haloperoxidases have been proposed for use as an anti-microbial agent.